add blank material files

valve/pbr/halflife.wad/+GYMLIGHT/+GYMLIGHT.mat

@@ -0,0 +1,8 @@
+
+{
+"for" "+AGYMLIGHT"
+//"basecolor_map" "+AGYMLIGHT.png"
+//"normal_map" "+AGYMLIGHT_normal.png"
+//"metal_map" "+AGYMLIGHT_metal.png"
+//"roughness_map" "+AGYMLIGHT_roughness.png"
+}